Hoo wee
If the fluff can be changed and the culture can be changed and the physical appearance can be changed, why not just change it all to human and be done with it?
Because it's easier to keep things as they are, rather than do that and force
the rest of the community to home-brew things apart again for elements of the game they already enjoy.
Never said free them from any and all stereotypes, just the ones that restrict then to stick with the fluff associated with a non-human race.
Okay. Specific, but
okay. There's ways to do that without completely cutting the race.
I don't see a direct correlation between writing/acting, and RP. In writing and acting there is the content creator and the audience. No such divide exists in RP the content creators are also the audience.
RP is literally role-playing, which is acting out the role you wrote mixed with improv. It doesn't matter who the audience is, if the same skills are needed. If I write a book, I'm writing a book regardless of whether it's red by me, my friends or perfect strangers.
Also, again, if all the fluff can just be changed, what's the big deal? Just make all the humanoids actual humans!
Why? People want the fluff they want. If they don't want omni-humans, then doing that is useless. There's no reason to do it unless you explicitly want to play the game that way, and if they wanted to, they already would! The only thing gained by a third party experiencing this change is appeasing you. If the fluff is loose enough to change, then the change to all-Human can't matter either. If these things are
soo human to you that they might as well be Human, then what problem exists with their current state of being? There's no reason to take the step you're proposing.
Get rid of classes and create a system that allows players to create whatever kind of character they want. My personal favorite fantasy RPG is Mythras, humans only, no classes, divine magic, wizard magic, monk mysticism, basic hedge-witch magic...best fantasy RPG out there IMHO! A true "toolkit" to make my feverish nightmares come true!
Okay, great! D&D doesn't have to change to be more like that, especially if something exactly like what you're looking for already exists.

This is the eye rolling emoji, right? If not, pretend it is!
Way to snub something that you should agree too. I wish I could be so evasive with such confidence.
What is the measure of player skill I wonder? Is it good RP? Then that would lead to circular reasoning, immediately! Character depth come through action in the narrative.
Why would it be "good RP"? That's an umbrella term. It'd be their imagination/writing/acting. Character depth comes from the consideration brought in by the player to the character's personality and mentality.
Some of the best roleplayers and deepest characters I have ever encountered were from people who were brand new to the hobby and not weighed down by years of stuffing themselves into "Elf" or "Dwarf" boxes.
That's nice, but adds nothing. Maybe players just need to learn how to step out of boxes, rather than avoid ever confronting them. Even then, it's not like this means that the option shouldn't exist.
Indeed it does. I worry about the negative far more than the positive because in order to make the world a better place we need to focus on fixing the negative parts, once that's out of the way we can dance and celebrate and raise our glasses high celebrating the positive.
My way of looking at it is this: If I took Orcs as is, and then made them look human and said they were human, would they all of the sudden not be offensive? No. The offensive part is what the context and characterization is doing, not the idea of an orc race, something whose meaning can change into something else. Also, why does something having more than one possible meaning make it meaningless? That's just arbitrary reasoning.
You don't just "not worry" about the positive of this topic, you completely deny that it does or could exist! I want the offensive things to be fixed, but you're basically using this as a vehicle to cut out a part of a game that is not the problem. There would never be a point to celebrate the fun of non-human storytelling of you took that same feature out to the back and put it down with a shotgun. This message of yours is agreeable and nice on the surface, but behind its face is something far less appealing.
Aside from that, you can't make the case for elimination of a feature if you keep explicitly refusing to see the value people are putting into it. Anything looks bad if you try to make it look bad.
I've seen the game change first hand.
Zarion. I know our personal experiences inform our worldview, but these things are not effective sample sizes for the community's practices, and even then, all it can do is inform whether or not you like things, not if it's "good". I don't care if the other races make for bad RP (which they don't), so long as people have fun. DnD doesn't have some obligation to facilitate the highest quality RP skills, it's for people to take that toolbox and use it. People are using it. Stop attacking the toolbox. Do I need to get the Cello metaphor back?
Back in the day when I ran Advanced Dungeons & Dragons 2nd Edition all the people at the game shop told stories about what was happening in the narrative of the game they were participating in. Now all the people at the game shop talk about is mechanics. I used to watch people describe how their character was shopping for new clothes or dancing at the King's Grand Ball. Now I watch them push minis around a battlemat and skip over the "boring" shopping trip. 5e was supposed to be a return to the days of old when RP mattered, except that doesn't sell minis or books full of even more mechanics. The saving grace is that I do get to watch and discuss RP as long as the players have "moved on" from D&D to systems that are less mechanics focused. D&D is the "800 pound Gorilla" as others have said. I wish it was used to increase the RP part of the hobby. The minis fights can be left to the minis combat games. I am very afraid, and not at all surprised, if 5e is the death of RP as RP and just becomes another minis combat game in the future. I don't want this hobby to die, but with D&D being always more focused on the "gameplay" crowd over the "roleplaying" crowd means it is leading the entire hobby in that direction. That makes me SAD!
Your problem is that the community has changed, as if it needs to return to the old. Maybe DnD just has more casual fans. I think RP is a good thing, but if people aren't doing that, then that's their prerogative. I'm sorry this isn't what you want, but you can play how you want still. It may not feel like it, but things
are okay in this situation. People may not enjoy things the same way, but isn't it important for them to be happy at all? I know you care about people having good experiences and developing, but you have to see that what you're working for isn't even in your own interest. You want them to advance? They already are. Be happy? They are. RP-ing? In their own way, they are. What's it matter how they play the game? DnD/WotC have problems, but this isn't something that needs fixing.